Salicylic acid alleviates growth inhibition and oxidative stress caused by zucchini yellow mosaic virus infection in Cucurbita pepo leaves

The effects of zucchini yellow mosaic virus (ZYMV) infection and pretreatments with salicylic acid (SA) on biomass accumulation of pumpkin (Cucurbita pepo cv. Eskandarani) were investigated. The response of photosynthesis, transpiration and the activities of antioxidant enzymes in leaves was also considered. Significant reductions in growth parameters (i.e. leaf area, biomass and shoot height), photosynthesis and chlorophyll a and b content were detected in ZYMV-infected leaves in comparison to healthy controls. Antioxidant enzyme activities were increased up to 3-fold for peroxidase (POD), 2-fold for ascorbate peroxidase (APX) and catalase (CAT) activities and 1.3-fold for SOD activity by virus infection. ZYMV infection also caused increases in H₂O₂ and malondialdehyde (MDA) contents. These results suggest that ZYMV infection causes oxidative stress in pumpkin leaves leading to the development of epidemiological symptoms. Interestingly, spraying pumpkin leaves with SA led to recovery from the undesirable effects of ZYMV infection. Leaves treated with 100 μM SA three days before inoculation had the appearance of healthy leaves. No distinct disease symptoms were observed on the leaves treated with 100 μM SA followed by inoculation with ZYMV. In non-infected plants, SA application increased activities of POD and superoxide dismutase (SOD) and inhibited APX and CAT activities.In contrast, SA treatment followed by ZYMV inoculation stimulated SOD activity and inhibited activities of POD, APX and CAT. In addition, MDA displayed an inverse relation, indicating inhibition of lipid peroxidation in cells under SA treatment. It is suggested that the role of SA in inducing plant defense mechanisms against ZYMV infection might have occurred through the SA-antioxidant system. Such interference might occur through inhibition or activation of some antioxidant enzymes, reduction of lipid peroxidation and induction of H₂O₂ accumulation following SA application.     

Salicylic acid alleviates growth inhibition and oxidative stress caused by zucchini yellow mosaic virus infection in Cucurbita pepo leaves

The effects of zucchini yellow mosaic virus (ZYMV) infection and pretreatments with salicylic acid (SA) on biomass accumulation of pumpkin (Cucurbita pepo cv. Eskandarani) were investigated. The response of photosynthesis, transpiration and the activities of antioxidant enzymes in leaves was also considered. Significant reductions in growth parameters (i.e. leaf area, biomass and shoot height), photosynthesis and chlorophyll a and b content were detected in ZYMV-infected leaves in comparison to healthy controls. Antioxidant enzyme activities were increased up to 3-fold for peroxidase (POD), 2-fold for ascorbate peroxidase (APX) and catalase (CAT) activities and 1.3-fold for SOD activity by virus infection. ZYMV infection also caused increases in H₂O₂ and malondialdehyde (MDA) contents. These results suggest that ZYMV infection causes oxidative stress in pumpkin leaves leading to the development of epidemiological symptoms. Interestingly, spraying pumpkin leaves with SA led to recovery from the undesirable effects of ZYMV infection. Leaves treated with 100 μM SA three days before inoculation had the appearance of healthy leaves. No distinct disease symptoms were observed on the leaves treated with 100 μM SA followed by inoculation with ZYMV. In non-infected plants, SA application increased activities of POD and superoxide dismutase (SOD) and inhibited APX and CAT activities.In contrast, SA treatment followed by ZYMV inoculation stimulated SOD activity and inhibited activities of POD, APX and CAT. In addition, MDA displayed an inverse relation, indicating inhibition of lipid peroxidation in cells under SA treatment. It is suggested that the role of SA in inducing plant defense mechanisms against ZYMV infection might have occurred through the SA-antioxidant system. Such interference might occur through inhibition or activation of some antioxidant enzymes, reduction of lipid peroxidation and induction of H₂O₂ accumulation following SA application.     

Phytotoxicity of Roundup Ultra 360 SL in aquatic ecosystems: Biochemical evaluation with duckweed (Lemna minor L.) as a model plant

Glyphosate-based herbicides (e.g. Roundup Ultra 360 SL) are extensively used in aquatic environment. Although glyphosate is more environmental favorable than many other herbicides, it may be exceptionally dangerous for aquatic ecosystems through high water solubility. Thus, the aim of the work was quantification of influence of Roundup Ultra 360 SL (containing isopropylamine salt of glyphosate as an active ingredient) on biomass and chlorophyll content within duckweed (Lemna minor L.). Moreover, changes in polyamine content and activity of such antioxidative enzymes as catalase (CAT) and ascorbate peroxidase (APX) were assayed in order to determine the biochemical mechanisms of L. minor response to the herbicide treatment. Obtained results showed that phytotoxicity of the herbicide was connected with decrease in chlorophyll-a, b and a+b content, and reduction of biomass growth. Roundup, similarly to some abiotic and biotic stressors, caused over-accumulation of putrescine, spermidine and total polyamines (PAs) within duckweed tissues. In addition an increase in CAT and APX activities suggested that stress generated by the herbicide treatment was at least partially connected with oxidative burst. Intensity of the duckweed responses to the herbicide was dependent on the applied herbicide level and/or duration of treatment.     

混合盐碱处理下蚕豆叶片生理指标的变化

为了研究蚕豆在混合盐碱胁迫下的生理变化,试验采用3种盐碱胁迫方式KCl/NaCl、KCl/Na₂CO₃、KCl/Na₂SO₄处理2周,测定蚕豆鲜重、丙二醛和脯氨酸含量、抗氧化酶活性等生理指标。结果表明,随着盐碱胁迫时间的延长,蚕豆鲜重表现为先升高后下降趋势,丙二醛和脯氨酸含量呈上升趋势,其中脯氨酸含量在处理11d时急剧增加;随胁迫时间的延长,4种抗氧化酶SOD、POD、CAT、APX活性增加幅度呈先升高后降低趋势,其中处理11d时,酶活性增加幅度顺序是SOD＞ CAT＞ APX或POD。结论:蚕豆盐碱胁迫中,SOD酶活性发挥首要作用,脯氨酸是一种重要的渗透物质。     

Elevated antioxidant response and induction of tau-class glutathione S-transferase after glyphosate treatment in Vigna radiata (L.) Wilczek

Glyphosate (N-(phosphonomethyl) glycine) is a broad-spectrum herbicide, acting on the shikimic acid pathway inhibiting 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), thus obstructing the synthesis of tryptophan, phenylalanine, tyrosine and other secondary products. It has also been reported to generate oxidative stress which influences the antioxidant response of target plants. The effect of glyphosate application on total protein, CAT, POD and GST activities was investigated and elevated expression of the oxidative stress enzymes was obtained after glyphosate treatment.Tau-class GSTs are plant-specific, and are chiefly involved in xenobiotics and oxidative stress metabolisms. Many herbicides and safeners have been known to selectively induce tau-class GSTs in different plant species. Here we also report the induction of tau-class GSTs after glyphosate treatment in the seedling roots of two Vigna radiata varieties (PDM11 and PDM54). GSH-agarose affinity chromatography and mass spectrometry revealed that the tau-class GSTs induced in the two varieties were different; the tau-class GSTs present in the untreated controls were also different in the two varieties. The present study highlights the elevated antioxidant response, the induction of tau-class GST and the genotypic variation in the type of tau-GST in control and glyphosate treated varieties of V. radiata.     

Photosynthesis and growth responses of grapevine to acetochlor and fluoroglycofen

Acetochlor and fluoroglycofen are herbicides used in vineyards to eradicate weeds. This present study characterized the effects of these chemicals on photosynthetic characteristics and the antioxidant enzyme system in non-target grape leaves. The results showed that acetochlor and fluoroglycofen reduced net photosynthetic rate in a dose-dependent manner, but also reduced or increased pigment contents, respectively. According to chlorophyll fluorescence measurements, acetochlor and fluoroglycofen decreased the photochemical efficiency of photosystem II in the light and increased non-photochemical quenching. These herbicides enhanced malondialdehyde contents and accelerated the superoxide anion production rate in dose-dependent manners, which might be associated with lower antioxidant enzyme activities, especially at higher concentrations of the herbicides. Acetochlor and fluoroglycofen inhibited grapevine growth in the growth season one-year after herbicide treatment, and stem height was inhibited by up to 55.4% and 88.0%, respectively. Taken together, these results suggest that both herbicides are detrimental for grape photosynthesis and this might be associated with increased oxidative stress in the first year, while growth inhibition in the second year might be due to after effects of herbicide treatment.     

Tolerance to paraquat-mediated oxidative and environmental stresses in squash (Cucurbita spp.) leaves of various ages

Paraquat is labeled for row-middle application on cucurbits, but drift to crop foliage is inevitable. Experiments were conducted to determine whether differential tolerance to paraquat existed among leaves of various ages in Cucurbita spp. (squash) and other plants, and to examine whether leaves tolerant to paraquat are also tolerant to other herbicides and abiotic stresses. Physiological responses to paraquat, including antioxidant activity, were investigated in squash leaves to identify mechanisms of paraquat tolerance. Although the level of paraquat tolerance differed by leaf age, cultivar, and species, the level of paraquat injury was lower in younger leaves than in older leaves in 14 of 18 squash cultivars and 5 of 12 other species tested. Cellular leakage and lipid peroxidation were consistently lower in the youngest leaf (leaf 4) than in the older leaves. Quantum yield and relative chlorophyll content were the same in all leaves of nontreated plants. Epicuticular wax content was higher in the youngest leaf than in leaves 1, 2, and 3 of cv. ‘Joongangaehobak’ and ‘Wonbiaehobak’. However, leaf cuticle content was not consistent with leaf ages. Differential leaf response to paraquat was partially correlated with the change in catalase, peroxidase, ascorbate peroxidase (APX), and glutathione reductase activities in nontreated and treated leaves. The APX activity in the youngest leaf was generally 2 times higher than in leaves 1-3 in both nontreated and treated plants. Ascorbate antioxidant levels were also higher in the youngest leaf than those in leaves 1-3. Leaves tolerant to paraquat were also tolerant to diquat and to abiotic stresses, low temperature and drought. However, tolerance to oxyfluorfen, which has a different mode of action than paraquat and diquat, was higher in older than in younger leaves. Higher tolerance to paraquat-mediated oxidative and abiotic stresses in young leaves of most squash cultivars might contribute to the differential prevention of oxidative damage in leaves of various ages.     

Nitric oxide reduces oxidative stress generated by lactofen in soybean plants

Nitric oxide (NO) is a molecule able to directly scavenge ROS and end chain reactions, which can be generated by some herbicides. This study aimed to evaluate whether the pretreatment of soybean plants with sodium nitroprusside (SNP) solution, a NO-donor substance, provides protection against oxidative stress generated by lactofen. Soybean plants were pretreated with SNP before lactofen application. The levels of lipoperoxides and photosynthetic pigments were quantified, and the activity of the antioxidant enzymes glutathione S-transferase (GST), superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) was assessed. Although lipid peroxidation was not completely prevented, NO was able to scavenge ROS generated by the lactofen action, avoiding the photosynthetic pigment breakdown. Consequently, ROS scavenging by NO leads to a decrease in the available substrate for the antioxidant enzymes SOD, CAT, and POD, which are essential to protect plants under oxidative stress situations such as absence of GST induction by H₂O₂.     

Impact of Exogenous Application of Salicylic Acid on Growth,Water Status And Antioxidant Enzyme Activity of Strawberry Plants (Fragaria vesca L.) Under Salt Stress Conditions

Irrigation with saline water can act as an alternate water resource and thus plays an important role in saving freshwater resources as well as promoting agriculture. Furthermore, salinity stress is considered one of the major abiotic stress factors, which strongly reduces crop productivity. In this context, the present work was conducted to examine the effect of exogenous salicylic acid (SA) application on salt stress tolerance of strawberry plants. For this purpose, strawberry plants (Fragaria vesca L.), three months old, were treated with three SA concentrations (0?mM, 0.25?mM and 0.5?mM), then subjected to 80?mM NaCl or not. After five weeks of treatment, growth responses, water status, photochemical efficiency and oxidative stress indicators were measured. The obtained results showed that irrigation with saline water negatively affected the growth parameters, the leaf water potential (LWP), the relative water content (RWC), the stomatal conductance (gs) and photochemical efficiency (Fv/Fm). While, the total protein content, the electrolyte leakage (EL), the malondialdehyde (MDA) and the hydrogen peroxide (H₂O₂) contents were increased in stressed plants compared to unstressed ones. Salt stress also leads to the activation of the antioxidant enzymes. However, the exogenous application of SA under salt stress conditions reduced the H₂O₂ accumulation, the electrolyte leakage and the MDA content. It has also improved the growth parameters, the LWP, the RWC, the gs, the Fv/Fm, the protein content and the antioxidant enzyme activities (POD, CAT and SOD) in the treated plants compared to those without SA application. Therefore, the beneficial effect of 0.25?mM SA on Fragaria vesca L. salinity tolerance may provide some practical basis for strawberry cultivation under saline conditions.

     

Activities of antioxidant enzymes and photosynthetic responses in tomato pre-treated by plant activators and inoculated by Xanthomonas vesicatoria

The activities of antioxidant enzymes and photosynthetic responses were investigated in tomato (Lycopersicon esculentum L. var.) pre-treated by plant activators and inoculated by Xanthomonas vesicatoria. Plants were sprayed with acibenzolar-S-methyl, ASM [Bion^® 50 WG (0.2 g l⁻¹)] and aqueous extract from dry necrotic tissue flour (VLA) of ‘Lobeira’ (Solanum lycocarpum) bush. Four days later, the plants were challenged with a virulent strain of X. vesicatoria, under greenhouse conditions. Tomato leaves were then assessed to determine the activities of the main antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), and ascorbate peroxidase (APX). A reduction of bacterial leaf spot severity was observed in plants treated by ASM (49.3%) and VLA (31.4%), without any in vitro inhibitory activity over the pathogen. Controls showed decreases in CO₂ assimilation, transpiration, photosynthetic rates, and stomatal conductance. Water use efficiency and carboxylation efficiency were strongly affected in ASM- and VLA-treated, in comparison to controls and healthy plants. The tested substances induced increases in SOD and CAT activities in a delayed enzymatic response typical in compatible plant–pathogen interactions. Measured at daily intervals, activities of APX and POX were significantly (ρ0.05) higher in treated plants than in controls, except for APX in ASM-treated plants where no difference was found when compared to controls. Only POX was clearly induced at the earlier stages after spraying the tomato plants with ASM or VLA. Our results suggest that late increases in antioxidant enzyme activities may play a role in mitigating oxidative damage in restoring the photosynthetic imbalance imposed by the expansion of bacterial lesions.     

海藻提取物对干旱胁迫下苹果砧木幼苗抗旱性和养分吸收的影响

以1 a生苹果砧木M9T337幼苗为试材,设置正常供水（CK）、中度干旱（MD）、中度干旱+海藻提取物（MD+SE）、重度干旱（SD）、重度干旱+海藻提取物（SD+SE）5个处理,研究海藻提取物对不同程度干旱胁迫下幼苗的生物量、光合特性、抗氧化酶活性、渗透调节物质含量和植株养分含量的影响。结果表明：在中度干旱胁迫条件下,植株总生物量较MD处理提高了15.4%,净光合速率较MD处理提高了12.1%,SOD、POD、CAT和APX活性分别较MD处理提高了4.5%、8.4%、30.6%、9.8%,可溶性蛋白和脯氨酸等渗透调节物质较MD处理分别提高了19.1%和13.1%,植株氮、磷、钾含量较MD处理分别提高了19.2%、22.7%和40.5%;在重度干旱胁迫下,叶面喷施海藻提取物后总生物量较SD处理提高了13.7%,净光合速率较SD处理提高了10.2%,SOD、POD、CAT和APX活性较SD处理分别提高了16.6%、18.1%、30.2%、8.9%,可溶性蛋白和脯氨酸等渗透调节物质含量较SD处理分别提高了14.1%和13.1%,植株氮、磷、钾含量较SD处理分别提高了12.4%、21.7%和38.4%。不同程度干旱条件下喷施海藻提取物均有良好的缓解效果,以中度干旱胁迫缓解效果更显著。     

水杨酸对不同灌水下限青花菜根系生长、根冠比及叶片抗氧化酶活性的影响

以青花菜为试材,采用大田和室内分析相结合的试验方法,研究了0.15 mmol·L-1的水杨酸(SA)对不同灌水下限(相对含水量75%,60%和45%)青花菜根系生长及叶片抗氧化特性的影响。结果表明:(1)随着灌水下限的降低,青花菜主根长、根干鲜重及过氧化氢酶(CAT)活性先升高后降低,根冠比、过氧化氢(H2O2)含量、超氧化物歧化酶(SOD)、过氧化物酶(POD)及抗坏血酸过氧化物酶(APX)活性逐渐升高。(2)SA处理改善了青花菜根系生长特性,降低根冠比,提高结球期抗氧化酶活性,其中60%灌水下限经SA处理后,根系及酶活性指标均与75%灌水下限保持相当水平。由此可知:以相对含水量60%作为灌水下限并配合0.15 mmol·L-1SA处理可以为青花菜高效节水灌溉提供理论支撑。     

Antioxidant role of propolis extract against oxidative damage of testicular tissue induced by insecticide chlorpyrifos in rats

Pesticides induce oxidative stress leading to generate free radicals and alternate the antioxidant or oxygen free radical scavenging enzyme system. This study was conducted to investigate the oral toxicity of chlorpyrifos toward male rat and the oxidative stress of the sub-lethal dose (9 mg/kg; 1/25 LD₅₀) on the lipid peroxidation level (LPO), reduced glutathione content (GSH) and antioxidant enzymes; catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione-S-transferase (GST) activities of testicular tissue. Also, the protective effects of propolis extract (50 mg/kg b.w.) alone or in combination with chlorpyrifos were investigated. The oral administration of chlorpyrifos significantly caused elevation in LPO level by 1.79-fold as compared to control. The activities of antioxidant enzymes including CAT, SOD, GPx and GST were decreased significantly (23.66%, 27.75%, 29.13% and 11.52%) as well as the level of GSH decreased by 21.97% in testicular tissue as compared to control animals. Co-administration of propolis extract with chlorpyrifos or alone in male rats decreased LPO level, normalized CAT, SOD GPx and GST activities, while GSH content was increased in testicular tissue. We conclude that propolis extract significantly reduces chlorpyrifos-induced oxidative stress in rat testis and the protective effect of the pre-treatment with propolis extract as attenuating agent could be due to its antioxidant properties.     

外源单宁酸对茶叶中农药胁迫作用的缓解效应

农药是控制病虫草害的重要手段,但农药也会对植物的氧化系统及营养品质产生影响。基于单宁酸的天然属性和结构特点,研究了在农药诱导的氧化胁迫下,叶面施用单宁酸对茶叶抗氧化系统和营养品质的潜在作用。与单独施用农药相比,加施10 mg/L单宁酸显著提高了茶叶超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)及抗坏血酸过氧化物酶(APX)活性,其中POD活性分别是空白对照、吡唑醚菌酯单独施用的4.69倍和3.13倍,APX活性比单独施用吡虫啉、联苯菊酯和吡唑醚菌酯分别提高了340.74%、114.71%和271.70%。此外,单宁酸显著提高了茶叶总抗氧化能力,提高了脯氨酸、还原型谷胱甘肽和茶多酚含量,降低了膜脂过氧化产物丙二醛的含量。单宁酸还提高了茶叶中维生素C、可溶性蛋白、咖啡碱和游离氨基酸的含量。综上,外源单宁酸能够激活茶叶抗氧化酶活性,影响抗氧化非酶物质的积累,缓解茶叶中农药胁迫带来的氧化损伤,最终提高茶叶品质。     

外源亚精胺对渗透胁迫下南瓜幼苗抗氧化酶活性等生理特性的影响

选用南瓜品种银辉2号为材料,以PEG模拟水分胁迫,采用砂培法研究了不同浓度外源亚精胺(Spd)对南瓜幼苗生长、活性氧代谢、抗氧化酶活性及非酶抗氧化剂和渗透调节物质含量的影响。结果表明:0.9、1.2mmol·L~(-1)外源Spd处理,使渗透胁迫下南瓜幼苗的生物量分别增加了43.40%和36.69%,根系O·2生成速率和膜脂过氧化产物MDA的积累量下降了56.33%、43.50%;0.6、0.9 mmol·L~(-1)Spd处理,不同程度诱导增强了根叶抗氧化酶活性,尤其以0.9 mmol·L~(-1)Spd处理效果最佳,根系和叶片超氧化物歧化酶(SOD)和抗坏血酸过氧化物酶(APX)活性分别为渗透胁迫下的2.00倍、1.83倍和5.47倍、2.40倍,过氧化氢酶(CAT)、过氧化物酶(POD)活性分别提高了410.89%、300.50%和276.25%、331.18%,叶片中脯氨酸(Pro)和可溶性糖含量提高了1.76倍、1.71倍,可溶性蛋白的积累量达渗透胁迫的1.49倍,维持了较高的渗透缓冲和调节能力,根系抗坏血酸(ASA)和谷胱甘肽(GSH)含量升高了2.88倍和2.41倍;渗透胁迫下0.9 mmol·L~(-1)外源Spd处理,抑制了活性氧(ROS)的生成,减轻了由此导致的氧化损伤,抗氧化酶活性的响应和ASA-GSH循环,保护了生物膜系统的稳定,渗透调节物质的含量变化,既维持了细胞与环境的渗透平衡,又增加了光合碳同化产物和蛋白质的积累。表明0.9 mmol·L~(-1)外源Spd维持了渗透胁迫下南瓜幼苗碳氮代谢的正常进行,减轻了胁迫对南瓜苗期的氧化伤害。     

<Emphasis Type="Italic">Sunflower Chlorotic Mottle Virus</Emphasis> in Compatible Interactions with Sunflower: ROS Generation and Antioxidant Response

Sunflower chlorotic mottle virus (SuCMoV) is a recently described potyvirus that causes systemic infections in sunflower plants leading to chlorotic mottling and important growth reductions and yield losses. Oxidative damage is expressed after symptom development in this host-pathogen combination. The involvement of antioxidant enzyme activities in disease susceptibility was studied in two sunflower lines differing in the intensity and rate of development of SuCMoV infections: L2 is more susceptible than L33. A transient superoxide production peak was detected in leaves of both lines before symptom development. H₂O₂ accumulation increased before symptom expression in infected plants of L33 but in L2 such increase was registered only after symptoms became evident. In healthy plants of both lines, superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) showed similar activity levels. In inoculated plants of line L2, but not in L33, SOD and CAT activities increased significantly before the appearance of symptoms, and APX increases were detected later. A 1 mM SA treatment effectively decreased SuCMoV accumulation in plants of L2 but it did not affect it in L33. This treatment increased H₂O₂ accumulation and prevented the increase in antioxidant enzyme activities in infected plants of L2. It is suggested that increases in antioxidant enzyme activities interrupted the signals generated by the increase in ROS, which may have otherwise triggered defence reactions in the host and thus, resulted in a compatible interaction.     

PEG胁迫下不同品系藜麦抗旱性评价

利用不同浓度PEG溶液模拟干旱胁迫，研究5种品系藜麦幼苗的形态、生理生化及光合特性，并对其进行耐旱性评价。结果表明：15%PEG处理下各品系藜麦株高增量、叶面积及生物量显著（P<0.05）低于对照，其中株高增量、叶面积、生物量下降幅度最小的品系分别是NK1、NK2和NK5，分别比对照下降了44.38%、25.39%和48.23%;随着干旱胁迫加剧, 各藜麦品系叶片内相对含水量显著（P<0.05）下降, 叶片的质膜透性、丙二醛（MDA）含量、脯氨酸（Pro）含量上升，15%PEG胁迫下NK2和NK3的Pro含量分别是对照的2.69和1.93倍, 超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）和抗坏血酸过氧化物酶（APX）活性均先升后降，SOD、CAT和APX活性在5%PEG处理下达到最大值, 而POD活性在10%PEG处理下达到最大; 随干旱胁迫增强，5种品系藜麦幼苗的净光合速率（P_n）、蒸腾速率（T_r）和气孔导度（G_s）降低，胞间CO₂浓度（C_i）先降后升，叶绿素（Chl）先升后降，其中NK5品系P_n下降幅度最小，比对照下降了51.15%。运用隶属函数法对藜麦抗旱能力进行综合评定，不同藜麦品系耐旱性为NK5>NK1>NK2>NK4>NK3。     

不同浓度安打对烟草幼苗MDA、CAT、APX和GPX的影响

在温室中培育烟草幼苗,至9叶1心时,在第9叶片上用微量注射器注射不同浓度的杀虫剂安打100μL,24 h后测定烟草幼苗MDA含量和抗氧化酶的活性。结果表明,安打导致烟草幼苗MDA含量降低,抗氧化酶CAT、APX、GPX活性下降。     

重金属Cd及施肥对马铃薯抗氧化酶系统的影响

采用土培盆栽方法,以两个马铃薯品种克新一号和费乌瑞它为材料,研究不同浓度Cd胁迫下对马铃薯抗氧化酶系统的影响以及施肥对受Cd胁迫马铃薯的调控。结果表明,随着Cd处理浓度的提高,两个马铃薯品种叶片中SOD、CAT活性呈先上升后下降的趋势,并与对照成显著性差异。费乌瑞它马铃薯叶片中POD活性也呈先上升后下降的趋势。克新一号随着Cd处理浓度的升高,叶片POD活性呈先上升后下降再上升的趋势。随着Cd处理浓度的升高,两个品种马铃薯叶片中MDA、脯氨酸含量则成明显上升趋势。在Cd处理浓度为10mg/kg时,施用有机肥使两个品种马铃薯叶片SOD、POD活性降低,克新一号马铃薯叶片CAT活性降低。施用无机肥对两个品种马铃薯叶片SOD、CAT活性无显著性影响。与施用无机肥相比,施用有机肥对Cd胁迫马铃薯的缓解效果更明显。     

NaCl胁迫下Si对甘草叶片抗氧化酶活性的影响

为探究NaCl胁迫下Si对甘草抗逆生理特性的影响,通过盆栽试验,研究不同浓度Si对甘草叶片抗氧化酶活性(SOD、POD、CAT)、MDA含量、质膜相对透性以及可溶性蛋白和脯氨酸含量的影响。结果表明,Si2(0.2g·kg-1)处理为最适浓度,可显著提高甘草叶片SOD、POD、CAT活性,与对照(Si0)相比,这3种酶活性在Si2处理下分别增加37.44%、26.98%、35.16%;Si3(0.6 g·kg-1)处理显著降低膜脂过氧化物MDA含量;增加质膜相对透性、可溶性蛋白含量;降低脯氨酸含量,MDA含量降低35.63%;质膜相对透性增加17.69%;可溶性蛋白含量增加36.62%;脯氨酸含量降低38.15%。由此可见,Si可以通过提高抗氧化酶活性来减轻活性氧及自由基对甘草叶片的毒害作用,即加Si可改善甘草在NaCl胁迫中的抗逆特性,缓解了NaCl胁迫对甘草的伤害。